Evaluation and Comparison of Intervertebral Disc Degeneration Models Induced by Cervical Instability in Rats

Creating intervertebral disc degeneration (IDD) models is paramount for basic research.Our investigation was to identify the commonalities and distinctions between two strategies for provoking IDD: the cervical dorsal muscles resection (CMS) and the facetjoints resection (FR).Thirty-two 3-month-old male Sprague Dawley rats were randomly into four groups: FR, CMS and two shams.For the CMS group, the cervical dorsal muscles was excised, whereas, the FR cohort sawed the bilateral facet joints of C5/6.Twelve weeks postprocedure, C5/6 intervertebral discs were collected, and the bone microstructure of C5 vertebrae were analyzed by Micro-CT.And the defect rates of C5/6 vertebral endplates and the intervertebral disc height (IDH) of C5/6 were measured as well.Finally, histological staining was employed to evaluate the disc degeneration scores (DDS).Twelve weeks post operatively, both CMS and FR groups demonstrated significant IDD, with the pronounced deterioration of vertebral endplates, a diminished intervertebral height, and a notably elevated disc degeneration score within the model rats.Yet, the two models also exhibited distinct features.Primarily, the FR rats showed a significant boost in vertebral bone volume fraction, a trend not visible in the CMS rats.Additionally, the CMS rats presented more advanced endplate deterioration.Lastly, the CMS rats revealed a reduced IDH and an elevated DDS in comparison to the FR rats.Both CMS and FR prove successful in causing IDD.Nonetheless, a comparison of the two models revealed a more profound degeneration of the intervertebral disc in CMS rats relative to FR counterparts.